1. Field of the Invention
The present invention relates to a case structure, and more particular to a case structure capable of preventing electrostatic discharge and blocking a leakage current.
2. Description of Related Art
Electrostatic discharge prevention has become an import subject of product safety in current electronic devices. To avoid damage of electrical components in the electronic device originated from the electrostatic discharge, one typical technique is to install a diode between two different grounds within the electronic device, as disclosed in U.S. Pat. No. 4,958,255.
In addition, when a user operates the electronic device, the electrostatic charge carried by the human body may also enter the electronic device through a seam of a housing of the electronic device to discharge. To address this issue, a conductor or a circuit board capable of electrostatic discharge prevention is disposed between the housing and electrical components. The conductor or circuit board is connected to a ground such that the electrostatic charges are conducted to the ground instead of hitting the electrical components in the housing. These techniques are disclosed by US20070121308 and US20060266544.
These techniques can only avoid the damage of internal electrical components caused by discharge of electrostatic charges entering the electronic device from outside the housing. However, these techniques fail to consider the fact that the motherboard module in the housing may generate a leakage current during use of the electronic device. This leakage current may be conducted to the housing of the electronic device to cause an electric shock. In addition, these techniques require additional components in the housing, which reduces the usable space within the housing as well as increases the cost of the electronic device.